In fluid flow machines, such as gas turbines or aircraft engines, air is drawn in and compressed along a flow channel and burned with fuel in a combustion chamber. Subsequently, the combustion gases are discharged via the flow channel to drive rotors in a turbine.
The flow channel is circumferentially surrounded by a casing structure. Because of the combustion gases, very high temperatures prevail in the flow channel, in particular in the region of the combustion chamber and the downstream turbine. Therefore, the casing structure surrounding the flow channel must be efficiently cooled to achieve lowest possible operating temperatures and thus to be able to use materials with low requirements in terms of high-temperature properties.
To this end, cooling air is passed into the region of the outer casing structure to dissipate heat. Moreover, insulations and heat shields are used in such casing structures to protect the outer components from excessively high temperatures.